Backplate for telephone sets



March 10, 1936.

G. A. LONG BACKPLATE FOR TELEPHONE SETS Filed July 29, 1935 47 6- l-PNEY Patented Mar. '10, 1936 UNITED STATES PATENT OFFICE BACKPLATE FOR TELEPHONE SETS George A. Long, Hartford, Conn., assignor to The Gray Telephone Pay Station Company, Hartford, Gonn., a corporation of Connecticut Application July 29, 1933, Serial No. 682,777

10 Claims.

shall be of maximum strength in order to materib 6 is formed by stamping on the back of said rially increase the difiiculty of successfully tampering with the mechanism within the case.

One form of a back plate embodying my invention and in the construction and use of which the objects herein set out, as well as others, may be attained, is illustrated in the accompanying drawing, in which- Figure 1 is a front view of my improved back plate showing a portion of the electrical apparatus applied thereto.

Figure 2 is a side view of the case of a telephone set applied to my improved back plate.

Figure 3 is an illustrative view showing the manner of applying the flanged piece to the base piece to constitute the back plate.

Figure 4 is a detail view, scale enlarged, of a fragment of the back plate illustrating the manner of constructing a bushing support for the receiver cord.

A frequent source of trouble has heretofore resulted in connection with telephone instruments owing to the fact that access may be obtained to the case by breaking the comparatively brittle cast iron back piece comprising the back plate of telephone instruments now in common use, and it is a purpose of my present invention to so increase the toughness and strength of the back plate as to prevent its being broken and thereby to render it extremely difficult, if not impossible, to gain access to the interior of the case by methods which must be employed in prder to prevent discovery.

Such a plate is illustrated in the accompanying drawing in which the numeral 5 denotes the back piece that is formed of extremely tough sheet metal, as steel, which is stamped to form. In order to render this piece extremely rigid a -case may be placed, the rib, therefore, serving a two-fold purpose in a manner to be hereinafter described.

In order to create a space behind the back plate 5 and also to provide a retainer for the edges of the case a flange is formed on both the front and the back faces of the back plate and extending completely therearound, said flange having heretofore been formed integral with the back plate. In my improved structure I make this flange of a separate piece of tough sheet metal, as steel, which is cut into two pieces and each of which is formed to the shape of onehalf of the bounding edge of the back piece, and V as illustrated in Fig. 3 of the drawing.

These flange pieces 8 are provided with openings 9 to receive lugs l0 projecting at intervals from the side edges of the back piece, said openings being enlarged at their outer ends so that the outer ends of the lugs may be headed to securely fasten the flange pieces in place, the flanges being sprung over similar lugs II at theends of the back piece and. the meeting ends of the flange pieces being secured together as by welding at the ends of the back piece. A notch I2 is cut into the flange pieces for one side of the base plate and a bushing support l3 for a receiver cord is nicely fitted into said notch and is secured in place as by welding as a permanent part .of said flange.

A bushing It extends between the support I 3 and a housing I5 for a bend in said receiver cord It, said bushing being fastened in place in any suitable manner as by extending its ends into a' hole in the support l3 and also into a hole in the housing l5 and as shown in Fig. l of the drawing. Said housing has a base plate ll projecting from its bottom edge on two sides, said base plate being secured to the back surface of the back piece as by electric welding or otherwise and projecting to the front of the base plate through a hole 18 0f substantially the shape of said housing. Switch hook pin supports l9 and 20 of tough metal, as steel, are secured to the back piece as by means of integral lugs projected through holes in the back piece, said lugs being headed at the back of said back piece. A switch hook barrier is secured to the back piece adjacent to the pin support l9, said barrier com- 4 prising a barrier plate 2| with a bent end 22 to prevent insertion of a wire or other instrument through the switch hook opening 23 to gain access to wires 24 within the case.

A barrier plate base 25 extends from the plate 2| and is secured to the back surface of the back piece, as by welding, a slot 26 being formed in the back piece and the plate 2| and the bent end 22 together with said slot being of such size that said plate and bent end may be passed through the slot from the back of the plate.

A locking pin lug 21 projects through a hole in the back piece, said lug having a base 28 which is secured to the back of the back piece as by welding or otherwise, said lug having a hole to receive a, pin projecting from the inner surface of the top of'the enclosing case 29 of the telephone set, said case being secured to the coin box case 30 as by means of a lock, in a manner common to telephone sets of this type. Notches 3| and 32 are formed through the flange pieces 8 on the back edges thereof preferably at the.

of a piece of metal secured to and bounding a plurality of edges of said plate and a second piece secured to the remainder of said edges to complete said rim, said pieces forming flanges bordering the back and front faces thereof the latter being formed to fit the edges of an enclosing case to be secured to said back.

2. A back plate for a telephone set, said plate including a back piece having a rim composed of a piece of metal of a certain shape secured to and bounding different edges of said plate and a second piece secured to the remainder of said edges to complete said rim, said .pieces forming flanges bordering the back and front faces thereof the latter being formed to fit the edges of an enclosing case to be secured to said back.

3. A back plate for a telephone set, said plate including a back piece having a rim composed of a piece of metal secured to and bounding a plurality of edges of said plate and a second piece secured to the remainder of said edges to complete said rim, said pieces forming flanges bordering the back and front .faces of said plate, the latter being formed to flt the edges of an enclosing case to be secured to said back and having holes therein, and lugs projecting from the edges of the back plate and secured in said holes to fasten said pieces in place.

4. A back plate for a telephone set, said plate including a back piece having a rim composed of two pieces of metal of similar shape each extending along a side edge of said plate and each having bent ends extending partially across the end edges of the back plate to abut the other bounding piece, lugs projecting from the side edges of the back piece and secured in holes in said bounding piece, and lugs projecting from the end edges of said back piece and secured in holes insaid bent ends. 1

5. A back plate for a telephone set, said plate including a back piece composed of sheet metal stamped to shape and to form a groove extending around the plate at a distance from its edges for the reception of telephone wires, and a separately formed flange secured to the edges of and bounding said back piece to flt the edges of an enclosing case to be secured to said back.

6. A back plate for a telephone set, said plate including a back piece composed of sheet metal stamped to shape with a groove in its front face extending therearound for the reception of telephone wires, the formation of said groove creating a rib stamped to shape at the back of said back piece, a rim formed of a separate piece of metal applied from opposite directions to opposite edges of the sides and ends of said back piece and forming flanges on the back and front faces of said back piece, and means for securing said rim pieces in place.

'7. A back plate for a telephone set, said plate including a back piece having a rim composed of two pieces of metal bounding opposite edges of said plate and forming flanges on the back and front faces thereof with a switch hook opening in one of said flanges, and a barrier separately formed from said back piece and secured in an opening therein relatively to said switch hook opening.

8. A back plate for a telephone set, said plate including a back piece having a rim composed of two pieces of metal bounding opposite edges of said plate and forming flanges at the back and front faces thereof with a notch comprising a switch hook opening in one of said flanges, and a barrier having a piece secured to the back of said back piece and projecting through an opening therein to the front face to prevent access through said switch hook opening to wires upon the front face of said backplate.

9. A back plate for a telephone set, said plate 4' including a back piece having a rim composed of two pieces ofmetal bounding opposite edges of said plate and forming flanges on the back and front faces thereof, a cable housing separately formed from said back plate and secured to the front face thereof, and a cable bushing projecting into said housing and extending through said flanges.

10. A back plate for a telephone set, said plate including a back piece having a rim composed of two pieces of metal bounding opposite edges of said plate and forming flanges on the back and front faces thereof, a cable housing located in an opening throughthe back piece and having a base plate secured to the back of said back piece, and a cable bushing projecting at its opposite ends into said housing and through said flanges.

GEORGE A. LONG. 

